is 2 21717953 - 1
has 6537756 decimal digits
takes 15.391 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
factored, 0 LL tests remaining
ResidueStatus
L-L635C76CFD3371955double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual27011.002464.2857 %1135000309287502.83436.3351 %13.836866.5482 %
Target2695.497163.7681 %160000225000001.41513.8399 %6.912365.1594 %
Difference+1+5.5053+0.5176 %+975000+8428750+1.4192+2.4952%+6.9245+1.3888 %

Known prime factors (1 factor, 72.7 bits, 0.00033463% known):
Remaining cofactor is PRP status unknown

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
2171795375372510377146294168392272.675173525816123523
33 × 277099 × 23193451
2020-04-132770992319345172.0901.56772.4252

P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2004-03-16Sturle Sundev4_computers2500005437500--0.5474.254%
2020-04-13gLausslaptop-klaus1135000309287501222272.6752.8346.918%


Trial Factoring results:
5758596061626364656667686970
 BitsFactor
dateuseridcompidfromtofactorbits*digitsGHz-days
2003-05-04FreeTibetv4_computers212670.688
2017-05-03ramgeisManual testing2672681.376
2017-11-28VictordeHollanderManual testing2682692.753
2018-05-03ramgeisManual testing2692705.505


ECM factoring results:
No ECM results for M21717953


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
2004-04-20Sturle Sundev4_computers635C76CFD337195515.39
2009-10-07gLausseis_neu635C76CFD337195517.62


PRP results:
No PRP results for M21717953


CERT results:
No CERT results for M21717953


P-1 factor-bounds graph:
B1 = 1135000, B2 = 30928750 (P-1 stage 2)
B1 = 1135000 (P-1 stage 1)
B1 = 250000, B2 = 5437500 (P-1 stage 2)
B1 = 250000 (P-1 stage 1)
104
105
106
107
104
105
106
107
108
TF factor-bounds graph:
270
269
268
267
this exponent TF target: 69
TF double-checked to: 67
250
260
270
280
JSON version of this page
Last modified: 2024-03-13T02:15:48+00:00